A label is often the primary resource for evaluating wine or beverages before making a purchase. Moreover, wineries place great importance on label design as appearance of label is known to influence wine buying choices. A majority of wine and beverage bottles use paper as label facestock because of its perceived superior aesthetic appearance and shelf appeal. Paper facestocks are however, susceptible to losing opacity when exposed to moisture, humidity and water during cooling or storing. During the period of cooling, liquid infuses into such facestocks and causes the appearance of the paper to change unacceptably. Additionally, the facestock might pucker, further reducing appearance.
It is also observed in certain cases that irrespective of the nature of the facestock being used in the label, moisture and related components can adversely affect the adhesive holding the label to the bottle and the label may become detached which causes identification even more difficult.
Attempts have been made or solutions have been proposed in the past to provide or improve general opacity of labels. These attempts, however either failed to recognize the opacity problem of labels in wet conditions, and were ineffective or expensive or both.
In addition to the past attempts to devise a solution to improve opacity in labels, the conventional art provides general solutions to dry opacity. The solutions include addition of pigments, such as titanium dioxide, calcium carbonate, aluminium silicate, calcined clay, kaolin clay, and zinc oxide. The pigments can be added to the paper facestock layer during the paper making process. The pigments can also be added as a coating layer such as an undercoat or topcoat on the paper facestock and the coat can be placed between the facestock and a pressure sensitive adhesive layer.
A significant limitation with those pigments is that many of those pigments such as calcium carbonate, aluminium silicate, calcined clay, kaolin clay, and zinc oxide show good dry opacity but exhibit poor wet opacity. Titanium dioxide even though showing better wet opacity, cannot be used in the suggested way because titanium dioxide is significantly expensive. Also manufacturers of labels do not have control on paper manufacturing so as to be able to incorporate desired levels of pigment into the paper. Moreover, use of pigments in coating layers involves multiple steps that are often complex requiring special processing requirement and thus adding further to cost of manufacturing. Thus utilization of the pigments, while attractive, has not been general.
Accordingly, a need exists for a new strategy for labelling articles so that the labels maintain a relatively high level of opacity when in a wet condition, while also maintaining adhesive properties.